This invention relates to an apparatus for connecting implantable electrode leads to an implantable device, and more particularly to an implantable connection device that may be used to connect cortical, deep brain (i.e., xe2x80x9cdepthxe2x80x9d), or other electrode leads from a patient""s brain to a device that is typically also implanted as an integrated portion of a system for detecting, monitoring, or stimulating electrical activity in a patient""s brain. The invention includes methods for use of the device.
Systems for electrically monitoring and stimulating the brain are increasingly important in the medical diagnosis and treatment of various brain disorders, such as epilepsy, Parkinson""s disease, sleep disorders, migraine, and psychiatric ailments. Therapeutic neurostimulatory devices may include one or more leads having at least one electrodes operatively situated in the brain or other neural tissue and linked to a signal processor for detecting neurological activity and to a pulse generator for providing electrical stimuli.
Many functional and aesthetic advantages may be achieved by implanting the signal processing and pulse generator portions of neurostimulator devices in the cranium. From a purely esthetic point of view, the electrode leads need not run along the scalp and down the neck. Connecting implanted electrodes to devices located in other regions of the body mandates that the electrode leads be lengthy. For instance, the Medtronic Activa(copyright) device uses leads that are tunneled along the neck and down the chest to the pectoral region where the neurostimulator resides. Such a pathway subjects the leads to increased risk of fatigue and to a higher susceptibility to noise from a variety of external electromagnetic sources. This inventive device assists in solving these very real problems.
One example of a system implantable beneath the scalp is found in U.S. Pat. No. 6,016,449 entitled xe2x80x9cSystem for Treatment of Neurological Disordersxe2x80x9d to Fischell, et al. (hereinafter xe2x80x9cFischellxe2x80x9d). Fischell et al discloses a responsive detection and stimulation system for the early recognition and prompt treatment of a neurological event arising from neurological disorders such as epilepsy, migraine headaches, and Parkinson""s disease. In Fischell et al""s device, the entire implantable portion of the system for treating neurological disorders lies beneath the patient""s scalp. By placing the entire system within the cranium, as opposed to extending wires into or through the neck to a control module in the chest, the probability of wire breakage due to repeated wire bending is drastically reduced. Other examples of devices implanted in the cranium for applying electrical stimulation therapies to electrodes situated at appropriate locations include cochlear implants.
Typical cranial electrode arrays are either brain surface electrode arrays or depth arrays. Brain surface electrodes often include an array of disk-shaped electrodes that are placed on the surface of the patients brain. The electrode arrays may be arranged in different formations and the number of electrodes per array may also vary. Depth electrodes are also usually small diameter leads having multiple distal electrodes on the same (or possibly branching) shaft. The major difference between the physical appearance of the two types is that the depth arrays are made up of a number of ring electrodes located distally on the lead. In either case, the proximal ends of the electrode leads may be arranged so that the those proximal contacts or termini are spaced along the shaft of the lead, electrically separated, one from the other. The physical separation of those proximal contacts is often via use of a non-conductive tubular portion, typically of the same material as the remainder of the electrode lead assembly""s shaft. In turn, the lead connector assembly links the electrodes of the lead to the implantable device. It is essential that the lead connector device reliably connect each of the electrodes without functional failure.
Accordingly, it would be desirable to have an electrode lead connection device which is implantable into a patient""s cranium. Such a device desirably ensures a reliable electrical connection between the electrodes and an implantable neurostimulatory or monitoring device. Furthermore, the lead connector should be easy for the surgeon to use and allow replacement of the neurostimulatory or monitoring device without having to replace the electrode leads.
This invention relates to an apparatusxe2x80x94an implantable lead connector assemblyxe2x80x94for connecting implantable electrode leads to an implantable device. The invention accepts at least one electrode lead and seats it within an interposer that in turn is secured inside a connector housing that can be electrically connected to an implantable device. The entire lead connector assembly is implantable. The interposer is adapted to seat an electrode lead and allow access to all of the proximal contacts on the lead via electrical conductive members in the inventive implantable lead connector assembly. Desirably, the step of securing the connector housing in the closed position compresses electrically conductive members situated within the connector housing into contact with the electrode lead, and simultaneously compresses the seal to electrically isolate not common electrical members, resulting in a reliable electrical connection between the electrode lead and the electrical conductive members. The electrically conductive members may project through the connector housing where they can link to an implantable device, such as a signal processor or stimulator, or, alternatively, the electrically conductive members may electrically connect to passthrough pins or wires that link to the implantable device. The inventive lead connector may accommodate several lead electrodes.
The electrically conductive members, when compressible, may take differing forms.
One preferred variation of the invention includes using at least one spring contact as the compressible electrical conductive member that contacts the lead electrode and an interposer capable of accommodating the spring contacts as well as the lead electrode.
Another variation of the invention uses a fuzz button connector as the compressible electrical conductive member that contacts the lead electrode when the assembly is secured, and also an interposer capable of accommodating the fuzz button connectors as well as the electrode lead.
Another variation of the invention includes a split interposer that cooperates with other components of the inventive lead connector assembly, e.g., the connector housing that also may be split and associated connector housing seals, so that the step of securing the connector housing also seals the lead electrode within the then-joined interposer.
Still another variation of the interposer obviates the need for fuzz buttons and spring clips by use of a formed or molded interposer having regions of conductive materials generally matching the spacing of the proximal contacts on the electrode lead.
The invention further includes a method of connecting an implantable electrode lead to an implantable device. The method involves inserting an implantable electrode into a patients brain and providing an implantable lead connector assembly and an implantable device. The implantable lead connector assembly includes an interposer, a connector housing, and a fastener such that the connector housing has compressible electrical connection members that can form electrical contacts with the electrode lead when the device is secured.